Mailboxes used in rural settings and in many suburban settings are formed as hollow box-like structures, typically with a curved top, and with a door at one or sometimes both ends of the box for access to the interior. These mailboxes include a flag that is pivotally mounted on one side of the mailbox to indicate to a mail carrier that the mail customer has placed outgoing mail in the box, so the carrier will open the box to remove the outgoing mail even if the carrier has no mail to be delivered to that box. When the outgoing mail is removed the carrier lowers the flag. If a mail customer has placed outgoing mail in the box and raised the flag to signal the carrier, the lowering of the flag by the carrier provides a visual indication to the owner of that mailbox that the mail carrier has opened the mailbox, and that mail may have been delivered.
When a mail customer has no outgoing mail, however, there may be no indication to the customer that the carrier has completed that portion of his or her route. Even if the carrier has completed that portion of the route, the customer has no indication that the carrier opened the customer's mailbox. Therefore, the customer must open the mailbox and check for delivered mail. In many instances a customer's mailbox may be a significant distance from, e.g., his or her residence, and a trip to the mailbox can be quite an undertaking, especially in inclement weather.
Various approaches to providing a visual indication that the mailbox has been opened, or that mail has been deposited in the box, are known in the prior art. Some approaches depend upon the mail carrier to activate the indicator, which is uncertain at best. Other approaches provide an indicator means that is triggered automatically when the door is opened or when mail is placed in the box. Some of these prior art approaches utilize electrical components to illuminate a light, and others use mechanical devices to raise a flag or otherwise signal receipt of mail. Both the electrical and the mechanical devices known in the prior art are relatively complex, and typically are installed in the confined interior of a mailbox. Devices known in the prior art are also relatively costly, and often require frequent adjustment and maintenance.